The invention is directed to an electrical connection system and connectors that resist inadvertent release. More specifically a connection system having a specially designed female connector that mates with a correspondingly specially designed male plug, in one exemplary embodiment, or a standard male plug, in another exemplary embodiment, and resists inadvertent release.
Electrical connection systems to date have generally included molded male plugs having two to three electrical elements, typically having at least two blades. These plugs connect to corresponding two and three element female connectors, for instance at a standard wall jack or extension cord terminus, and carry electricity to various devices. The tenuous connection between the components of a typical electrical connection is facilitated by a friction fit of the electrical elements within the respective female terminus. Often, in light duty work, this simple friction fit is sufficient.
However, as more communities limit the use of gasoline powered devices for outdoor use, heavier duty outdoor use of electrically powered devices and the power cords that supply them with electricity is on the rise. These devices are being used increasingly by both homeowners and professionals in these heavier duty applications, for example in lawn care applications. In numerous indoor applications, for example, when using hand held saws and drills in a workshop, a standard friction fit is often also insufficient. Therefore, there is an increased need to maintain electrical connections to these devices for the sake of efficiency and safety in commercial and non-commercial applications.
Although several attempts at achieving improved electrical connections that resist disconnection have been made in the past, they all have significant shortcomings. Often in the heretofore known solutions, the safety of the consumers and their children and the potential for accidents has been overlooked. The electricity carried by electrical power cords from electrical outlets to a multitude of electrical devices can be highly dangerous. It is quite capable of inflicting serious injury or even death to anyone who comes into direct contact with it, but especially children.
Dangerous contact with large amounts of electrical energy can happen in many ways. For instance, a partially plugged in electrical connector is still capable of carrying electrical energy to contacted body parts, especially the small fingers of children, resulting in electrical shock.
Another danger arises from intermittent engagement of electrical devices that are partially plugged in, especially in outdoor use of heavy electrical equipment, such as the user of trimmers and power saws. The user of the electrical device may turn the device on, observe no action, and assume the device is not powered. However, a slight jostling of the electrical cord may provide power to the device unbeknownst to the user. The user may have been treating the powered device as though it were not powered, and serious injury may result.
Another potential danger arises if, in attempting to cut power in an emergency, the electrical plug has a plug-locking device that cannot be easily reached or disengaged. In this situation, the heretofore known locking electrical plugs that were designed and built to safely maintain an electrical connection become hazards unto themselves.
The inherent dangers of handling electricity are not new, nor are the concepts of locking electrical connectors and connector systems. Many designs exist for locking electrical plugs as a solution to these dangers. However, the majority of these solutions, while providing for maintenance of these connections against accidental disconnection, provide little or no consideration for safe and immediate disconnection of the electrical connections in emergency situations. In fact, these designs do not meet Underwriter""s Laboratories (hereinafter UL) guidelines and, therefore, are not approved by this recognized consumer safety organization.
UL has written safety guidelines for the minimum and maximum safe pulling forces that should be applied to remove an electrical plug from an outlet to help mitigate these risks. These guidelines are published in the UL publication Standards For Safety for Attachments, Plugs and Receptacles, incorporated herein by reference, and rule 498 of this publication specifies a minimum of between three (3) pounds pulling force and a maximum of fifteen (15) pounds pulling force for disconnection in household use. In the heretofore known lockable plug designs, with few exceptions, these specifications have not been heeded.
Several designs attempting to improve the standard electrical connection modify the male plug in an electrical connection system. Many of these existing designs require the presence of a ground pin to function (e.g. Brock, U.S. Pat. No. 5,249,976, Warren, Sr. et al., U.S. Pat. No. 5,082,450, and Imhoff, U.S. Pat. No. 4,544,216). Although the use of ground pins is generally accepted as safer than the alternative, their use is hardly universal. Moreover, no consideration is given to the safe, rapid release of the electrical connection without engaging a release member.
Similarly, other locking plug designs require the use of a turning tool, typically used in conjunction with the male connector (e.g. Propp, U.S. Pat. No. 5,194,013 and Cohen, U.S. Pat. No. 3,345,603) to disengage blades or ground pins. Unplugging these plugs without their respective turning tools, which may not be available in an emergency situation, would require forces well outside those of the stated UL Labs safe maximum pulling force and suffer from similar problems as those with release mechanisms.
These existing locking plug designs, e.g. Brock, U.S. Pat. No. 5,249,976, Murchison, U.S. Pat. No. 3,390,404, Bergwall, U.S. Pat. No. 3,676,831, Baker et al. U.S. Pat. No. 3,267,408, Hime, U.S. Pat. No. 3,187,291, and many others like them, simply do not disengage by pulling on the electrical cord with a deliberate amount of force, especially within the specified force of the UL Guidelines. To release these plugs in an emergency would require forces that would destroy the plug or the receptacle to which they were attached. These plugs are, therefore, an inherent safety concern. The inability or difficulty in disengaging these devices in emergency situations outweighs the limited benefits provided by the increased resiliency in the electrical connection.
Even U.S. Pat. No. 6,050,831, to Duhe, Jr., which specifically mentions the UL guidelines, still requires depressing an external shaft that contacts a securement arm internal to the plug body to engage and disengage the plug. A user wishing to release the locking mechanism has to apply pressure to the shaft to achieve an unlocked position. Thus there still exists a problem with effectuating quick release of the electrical connection. Although the plug may be pulled free with forces within the specified UL guidelines in an emergency, doing so results in damage to the plug. Additionally, with Duhne, as with all the other locking plug designs, there is a significant increase in the number of components and manufacturing steps needed to produce the plug. This makes all of these designs prohibitively complex and costly for mass production.
In regards to known female connector designs that resist release, a series of marine or heavy-duty industrial locking type electrical connectors are well known in the art. These locking connectors do not consider safe release of the connection as an important feature. For instance, U.S. Pat. No. 5,641,310 to Tiberio, Jr. is just one example of such a locking system where typically a male blade assembly with specially adapted blades, is designed to engage a corresponding locking cut-out in a female connector and thereby lock the connectors. This requires a twisting motion to lock and unlock the connectors and cannot be pulled apart to effectuate safe disconnection. Additional examples of these types of systems include U.S. Pat. No. 5,741,149 to Anthony and U.S. Pat. No. 5,680,926 to Sandor et al.
Other female electrical connectors that carry projections are also known in the art. Patents such as U.S. Pat. No. 5,803,770 to Swendson et al. describes female connectors with projections. These devices utilize these projections as alignment guides. The guides do not assist in safely maintaining a releasable connection against accidental disconnection. Similarly, U.S. Pat. No. 5,993,255 to Yurko discloses an electrical connector assembly with a high-density plug connector that includes a female terminal with resilient latches. However, even these latches must be engaged using a mechanical assist device and they do not consider safe release of the electrical connection in emergency situations.
Thus, in all of the heretofore known designs, a user is required to physically damage the locking plug or the electrical outlet to unplug the electrical connection in an emergency without operating an external release mechanism or performing a special release function. Additionally, manufacturability, and thus product reliability at a reasonable cost to the consumer, is rarely addressed, especially with older locking plug designs.
Therefore, a need exists for a locking electrical system capable of remaining connected under rigorous usage, capable of remaining plugged under the small pulling forces experienced during normal use and also the small forces provided by children, and capable of being unplugged by the application of a reasonable pulling force without the need for activation of an external release mechanism. In addition, there exists a need for a locking electrical plug that is reliable and cost effective to both produce and purchase, and one that can be implemented easily in existing devices.
An advantage of the instant invention includes providing an improved electrical connection system for mechanically resisting disconnection.
A further advantage is providing an improved electrical connector, which meets or exceeds UL guidelines for release forces.
An additional advantage of the instant connection is a cost effective solution to provide an electrical connection that resists disconnection, but is safe in emergency release situations.
A still further advantage of the instant invention is the added safety of not having to depress a release mechanism to effectuate release.
Yet another advantage of the instant invention is that the female connector can be used with a conventional plug to provide a resilient connection.
A still further advantage of the invention is an improved electrical connection system that can be incorporated in a wide variety of applications and uses.
The invention includes an electrical receptacle and an electrical connector system.
The electrical receptacle includes a body member, the body member having at least one blade-engaging member with a first and second portion spaced apart from one another, a bridge portion, and at least one side structure spaced between the first and second portion. The receptacle also has at least one electrical lead coupled to the body member and at least one protrusion located on the body member that releasably engages and disengages a corresponding blade member absent the presence of an externally actuated release mechanism.
The electrical lead can be coupled to the blade-engaging member. The side structure can be a portion of the body member. The at least one protrusion can also be on the blade-engaging member. The side structures can also extend from the first portion of the blade engaging member. The at least one protrusion can be located on the first portion of the blade engaging member. The at least one protrusion can be located on a side structure. A further aspect of the invention includes an at least one protrusion that can be located proximate to an end of the at least one side structure portion, closer to but spaced from the bridge portion.
The at least one protrusion can have first more gradual slope extending from the at least one side structure of the first and a second sharper slope returning to the at least one side structure, defining a highest point for engagement between said first and second slopes. The first slope can extend from the at least one side structure at an angle of between about 3 degrees to about 45 degrees relative to the side structure. The second slope can return to said side at an angle of between about 20 degrees to about 85 degrees relative to the side structure. The at least one protrusion can be, in an exemplary embodiment, between about 1 mm and about 10 mm in length, between about 1 mm and 10 mm in width, and between about 0.5 mm and about 5 mm in height. The at least one protrusion can have a diameter of between about 1 mm to about 10 mm. The at least one protrusion can be one of a circular, ovoid, teardrop, and rounded shape.
The at least one protrusion can be shaped to engage a corresponding number of receiving portions or recesses in a blade member. The at least one protrusion can further include only a single protrusion on said blade-engaging member. The at least one protrusion can include multiple protrusions.
The at least one protrusion can also be located on the second portion of said blade-engaging member to engage a corresponding receiving portion or recess in the blade member. The protrusion can further include a first part of the protrusion closer to a first end of the body member having a gradually rising slope from the second portion and a second part located further from the front end of the body member, having a sharply angled second slope returning to the second portion. The electrical receptacle can have a first slope that rises from the second portion at an angle of between about 3 degrees to about 45 degrees. The electrical receptacle can have a second slope that returns to the second portion at an angle of between about 20 degrees to about 85 degrees.
The electrical receptacle can further include both a first protrusion and a second protrusion. The first protrusion can be located on said first portion, on an at least one side structure extending from the first portion. The second protrusion can be located on the second portion of the body member, near an end of the second portion closest to a receiving end of the body member. The first protrusion can engage a corresponding first receiving portion and said second protrusion can engage a corresponding second receiving portion in the blade member.
The electrical receptacle can further include an at least one blade guide channel corresponding to the at least one blade-engaging member. The at least one blade guide channel can precede the corresponding at least one blade-engaging member and guide a corresponding blade member to the at least one protrusion on the at least one blade-engaging member. The at least one blade-engaging member can be substantially shorter than said at least one blade, so as to necessitate full insertion of the blade into and along the blade guide channel to fully engage the blade-engaging member.
The said at least one protrusion can be a component of an electrical switch, where the switch is actuated by fully engaging the blade-engaging member and, thereby, the at least one protrusion. The electrical switch can be, for example, at least one of a contact switch and an electrical interrupt switch.
The electrical receptacle can further include at least one adjustment mechanism to adjust the at least one protrusion. The adjustment mechanism can effectuate a change in the position of the highest point for engagement between the two slopes. The at least one adjustment mechanism can be at least one of a screw, a resilient member, a ratcheting bolt or other adjustment mechanisms.
The electrical receptacle can further include having a visual indicator to indicate different ranges of disconnection forces for releasably engaging and disengaging the corresponding blade in the electrical connector. The visual indicator can be a color-coded body member.
The electrical receptacle can include a first portion of said blade-engaging member that terminates adjacent the bridge portion and a first side and a second side structure that extend therefrom.
The electrical receptacle of the instant invention can be mounted in a wall plug. The instant invention can also be modified for at least one of 110, 220, 440, and 660 volt applications.
The protrusion can disengage the blade upon an application of force of at least about three pounds force and at most about fifteen pounds force.
The system of the invention includes an electrical connector system having a male plug member with at least one blade and at least one recess. The electrical connector system further includes a female connector having at least one blade-engaging member, the blade-engaging member having a first portion, a second portion, at least one side portion located between the first and second portion, a bridge portion and at least one protrusion. The at least one protrusion being located along the blade-engaging member and engaging the at least one recess on the male plug member.
The system can have a first and second blade and a ground member. The system can further include one blade-engaging member, which engages the first blade. The electrical connector system can further include first and second blade-engaging members, each engaging respective first and second blade in a corresponding first and second recess.
The at least one protrusion can engage a corresponding side of the blade furthest from the body member. The female connector can also be housed in a wall outlet.
The apparatus of the invention also includes means for conducting electricity. The means for conducting electricity is coupled to the means for engaging an electrical connection and has at least one protrusion for resistively engaging and disengaging said connection absent an external release means.
Moreover, the above objects and advantages of the invention are illustrative, and not exhaustive, of those that can be achieved by the invention. Thus, these and other objects and advantages of the invention will be apparent from the description herein, both as embodied herein and as modified in view of any variations which will be apparent to those skilled in the art.